This narrows down my search and makes it quicker to get the information that I am looking for. It takes some time to get familiar to all the terms and how to use them in combination but but over the last few months I have found myself using Soople some times.
Soople provides an interface that makes it easy to make up the advanced Google queries and it also uses Google to do the search.
While the interface is a very busy one its quite a handy site once you get to know how is works.
Another site that does a similar thing is OnlyJust and I think its more useful if you want to search some Google search categories like blogs, images, code and so on.